A 4-stroke internal combustion engine typically comprises an intake valve for drawing an air/fuel mixture into a cylinder's combustion chamber and an exhaust valve for allowing combustion byproducts to escape from the chamber. A spark plug ignites the air/fuel mixture in a cylinder to move a piston, connecting rod, and crankshaft to provide power to the engine. These components are typically controlled by an engine control unit (“ECU”), which controls, among other things, the timing of fuel injection, the amount of fuel to be injected, and the timing of the spark. The spark time can be controlled to adjust the amount of combustion in a cylinder, and thus the force exerted on the piston, connecting rod, and crankshaft.
In typical fuel injection engine systems, it is desirable to know the position of each cylinder in order to properly time fuel injection. Commonly, a cam sensor, or a sensor on the cam shaft, is utilized to determine engine phase. However, for some engines it is desirable to eliminate the use of a cam sensor, such as to reduce cost and complexity of an engine or where installation of a cam sensor is difficult and presents quality control issues.
U.S. Pat. No. 6,109,986 discloses an idle speed control system for a marine propulsion system. The system controls an amount of fuel injected into the combustion chamber of an engine cylinder as a function of the error between a selected target speed and an actual speed. The speed can be engine speed measured in revolutions per minute or, alternatively, it can be boat speed measured in nautical miles per hour or kilometers per hour. By comparing target speed to actual speed, the control system selects an appropriate pulse width length for the injection of fuel into the combustion chamber and regulates the speed by increasing or decreasing the pulse width.
U.S. patent application Ser. No. 14/489,075 discloses systems and methods for controlling internal combustion engines having a plurality of piston-cylinders that cause rotation of a crankshaft. A crankshaft sensor is configured to sense rotational speed of the crankshaft, and a controller is configured to calculate an acceleration for each piston-cylinder based on the rotational speed of the crankshaft and then balance the accelerations of the respective piston-cylinders by modifying a combustion input to one or more of the piston-cylinders in order to reduce engine vibration.
U.S. Pat. No. 5,701,865 discloses a method of adjusting idle spark for an individual cylinder of an internal combustion engine in an automotive vehicle, including the steps of determining crankshaft acceleration for an individual cylinder of the internal combustion engine and determining an average acceleration error for the individual cylinder based on the determined crankshaft acceleration. The method also includes the steps of determining an adaptive spark advance for the individual cylinder based on the determined average acceleration error and determining a new spark advance for the individual cylinder based on the determined adaptive spark advance and a nominal spark advance. The method further includes the steps of adjusting idle spark for the individual cylinder based on the new spark advance for the individual cylinder.
U.S. Pat. No. 6,571,776 discloses a method for controlling start of a compression ignition engine having a plurality of cylinders and without a cam sensor is provided. The method comprises providing a respective fuel delivery assembly for each cylinder and retrieving from memory a set of fuel delivery assembly firing rules and processing the firing rules so that a firing signal is delivered to each fuel delivery assembly on every crank revolution during a cranking mode of operation. The fuel delivery assembly is arranged to be responsive to any firing signal received during an injection window leading to a top position along the longitudinal axis so as to supply fuel to each cylinder during the injection window. The fuel delivery assembly is further arranged to be insensitive to any firing signal received during an exhaust stroke leading to the top position along said longitudinal axis so that no fuel is delivered to each cylinder during that exhaust stroke.
U.S. Pat. No. 6,889,663 discloses a method for controlling start of a compression ignition engine having a plurality of cylinders without a cam sensor. The method comprises providing a respective fuel delivery assembly for each cylinder. In one embodiment, the method further comprises retrieving from memory a set of fuel delivery assembly firing rules and then processing the firing rules so that a firing signal is delivered to each fuel delivery assembly on every crank revolution during a cranking mode of operation. The fuel delivery assembly is arranged to be responsive to any firing signal received during an injection window leading to the top position along the longitudinal axis so as to supply fuel to each cylinder during that injection window. The fuel delivery assembly is further arranged to be insensitive to any firing signal received during an exhaust stroke leading to the top position along said longitudinal axis so that no fuel is delivered to each cylinder during that exhaust stroke.
U.S. Pat. No. 7,069,140 discloses methods of cranking and/or operating an engine that eliminates the need for use of a cam sensor. The methods involve manipulating fuel injection command signals to occur out of their proper sequence, monitoring an engine indicator responsive to firing and non-firing of cylinders, and identifying correct engine phase based on fluctuations in the engine indicator. Also disclosed are software product embodiments comprising program code modules that cause an engine control unit to manipulate the generation of fuel injection command signals to take place outside of their correct sequence.
U.S. Pat. No. 7,155,330 discloses a method for controlling start of a compression ignition engine having a plurality of cylinders without a cam sensor. The method comprises providing a respective fuel delivery assembly for each cylinder. In one embodiment, the method further comprises retrieving from memory a set of fuel delivery assembly firing rules and then processing the firing rules so that a firing signal is delivered to each fuel delivery assembly on every crank revolution during a cranking mode of operation. The fuel delivery assembly is arranged to be responsive to any firing signal received during an injection window leading to the top position along the longitudinal axis so as to supply fuel to each cylinder during that injection window. The fuel delivery assembly is further arranged to be insensitive to any firing signal received during an exhaust stroke leading to the top position along said longitudinal axis so that no fuel is delivered to each cylinder during that exhaust stroke.
U.S. Pat. No. 5,562,082 discloses an internal combustion engine having a crankshaft sensor with an uneven tooth spacing to identify an index tooth corresponding in position to top dead center (TDC) of the number 1 cylinder. A microprocessor based engine controller determines from the sensor pulses each TDC event. During cranking, the number 1 cylinder compression stroke is detected from engine speed variations by measuring time periods over sample ranges before and after TDC. When a compression stroke occurs just before TDC, the period before TDC is greater than the period after TDC, whereas other TDC events are evidenced by the period before TDC being smaller than or equal to the period after TDC.
U.S. Pat. No. 5,758,625 discloses a method of generating a phase signal over 7200 for an internal combustion engine comprises a multi-point electronic injection system operating sequentially, permitting firing in only some of the cylinders during the starting stage and detecting an angular position in which the first firing occurs.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.